This invention relates to a touch responsive apparatus which controls the characteristics of a musical sound such as volume and tone color according to the state of depression of an operated performance key of an electronic musical instrument, for instance the speed of depression of the key or the depressing force.
Touch responsive devices which control the volume and tone color of a musical signal according to the key depression speed have been developed. With such devices, however, it is only possible to obtain a keen sound of high volume when the key depression speed is high and to obtain a soft sound of a low volume when the key depression speed is low. A soft sound of a large volume, for instance, cannot be obtained. Therefore, it is impossible to obtain musically rich expression as is obtainable with a natural musical instrument. Further, with the aforementioned known apparatus, touch response is provided for each key in an analog fashion. Therefore, the hardware of the electronic musical instrument is extremely complicated, leading to increased cost and unstable operation.